1. Field of the Invention
This invention relates to an electrical cable reel for use in mining operations that is mounted to the side of a mining vehicle; the reel stores sufficient cable and is capable of winding and unwinding the cable as the vehicle moves about in a mining tunnel.
2. Description of the Prior Art
Almost all power utilized to operate equipment and machinery in mining operations is electrical. Mining operations require highly specialized equipment that either dump, haul, or bore tunnels into the rock or other strata as they move about in mining operation. These vehicles have to be moveable, and they have to have the capability of operating in confined, small locations, like mine tunnels. A typical vehicle would be a miner. A miner is a vehicle which bores into the rock, or other strata by the use of tools and other implements on the front of the vehicle. The rock ore that has been excavated at the front end, is conveyed to the rear of the vehicle, and dumped into other vehicles for hauling to other locations or for removal to surface. These vehicles are operated by electricity from flexible cables that carry very high voltage. The fact that these vehicles are moveable requires that they be capable of carrying their own electrical cable so that they always have direct power, sufficient for their operation. The handling of the cable is a major problem since the vehicles move about freely and the excess cable must be handled in some way, and there must be sufficient cable stored to permit travel to work stations. In the past, most mining vehicles that were electrically driven employed manual labor of individual workers, who simply dragged or reeled the electrical cable as the machine or vehicle moved about in the mine tunnels. Such work was dangerous, because of standing water, high voltage, and heavy cable.
There are, however, numerous known mechanical devices for spooling and/or handling electrical cables of mining vehicles as they move about in mining tunnels. All known devices have inherent defects or problems involved with their use.
The single most serious problem of known devices is the method or transferring electrical current from the cable to the vehicle. In most known devices, a rotating drum or reel is utilized onto which the cable is spooled. In all devices that utilize rotating drums to reel the cable, slip-rings, rotating collector rings, brushes or the like are employed to transfer power from the cable to the mining equipment. Two of many examples are U.S. Pat. Nos. Dudley 3,061,233, and Tschurbanoff 4,583,700. Others employ the same technology. These slip rings and the like are potentially dangerous in mining operations. Mining regulations (see part 18.43 of 30 CFR ch 1 of Mine Safety and Administration) require that all such slip-rings and the like be contained within explosion proof boxes and even when that is done, those connectors are unreliable and wear prone, due to the severe environment conditions of a mine. They are also expensive, complicated, and ineffective. Additionally, the explosion proof enclosures are large and utilize excess amounts of space on the mining vehicle.
A more recent system for storing cables is described in U.S. Pat. No. 4, 258,834, issued to Hawley. There, no slip-rings are employed. There, cable is dumped or pulled into or out of a large drum. The cable is fed through a round sleeve in which are disposed frictional devices which engage the cable and pull it into the drum. Many problems exist with this device. One is that not all cable is round. Some cable is flat, oblong, etc. The devices makes no allowance to handle other than round cable. The stationary drum of Hawley, does resolve the electrical connection problems the cable to be connected directly to the vehicle without the use of slip rings or dangerous connectors.
The device contained in Hawley, however, has some additional problems that are inherent in the design of the device, and other prior art stationary drum applications. In Hawley, the cable is deposited into a drum by a rotating arm, and the cable is supposed to stack systematically, simply by the weight of the cable forcing it into place. The problem is that the cable is pulled into the drum by friction type devices which squeeze the cable and pull it through the feeding fair-lead. Once the cable is clamped and squeezed, it restricts twisting of the cable, so when the cable is dumped into the container, it will twist, wrinkle, and not stack in any uniform manner. Such stacking decreases the available space for storage of the cable in the drum, and is, in reality, not usable for the reason above. Space, particularly for the drum storage of electrical cable, is very limited and must be kept to a minimum. There is no method available to utilize another known element to systematically stack the cable. The design is defective.
Another problem with Hawley is that most mining vehicles must utilize the rear of the vehicle for mining operations. In Hawley, the container and storage bin is directly behind the vehicle and that location is noted as being essential to its usage. Such a device could not be used in most mining vehicle applications, simply because of the position of the drum. As previously noted, the rear of most mine vehicles can not be utilized for reeling of cable because of other operations, such as hauling and dumping of ore. The miner, for instance, cuts rock from the front and conveyors it to the rear for dumping and hauling. The drum of Hawley could not be used with a miner or other vehicles utilizing the rear of the vehicle. In operation it is also desirable that the unwound cable be placed at the side of the tunnel. If the cable is disposed or unwound and placed into the middle of the tunnel, it gets in the way of all other vehicles that may be moving in or about the tunnel. Such cables impede traffic flow, and cause safety problems for other vehicles.
Lastly, cables have splices and are irregular in shape, and the device in Hawley does not provide for the variable size or shaped cables. Such splices, etc., could jam Hawley and make it inoperable and dangerous.
There are devices like Dudley, supra, that utilize side mounted rotating reels. However, there is no known device which use a stationary side mounted reel for the storage and unwinding and winding of electrical cables, in mining vehicles.
These and other problems of the prior art devices are resolved by the present invention, which is described hereinafter.